Kiln for burning cement, lime, &amp;c.



No. 688,345. Patented D60. l0, I90l. H. SCHIMDT.

KILN FOR BURNING CEMENT, LINE 8w.

(Application filed Aug. 2, 1900.)

(No Nodal.)

m: cams PETERS c0, mo'ro-u'ma, wnmnorou. n. c.

' sired in quality and physical properties. The

UNITED STATES PATENT OFFICE.

HERMANN SCHMIDT, OF 'BQNN, GERMANY.

KILN FOR BURNING CEMENT, LIME, 81.0.

SPECIFICATION forming partof Letters Patent No. 688,345, dated December10, 1901.

Application filed August 2, 1900- To all whom, it may concern:

Be it known that I, HERMANN Soar/nor, a citizen of Germany, and aresident of Bonnon-the-Rhine, Germany, have invented certain new anduseful Improvements in Kilns for Burning Cement, Lime, and the LikeSubstances, of which the followingis a specification.

Modern cement-kilns are constructed with the object of avoiding thelengthy drying process to which the slurry-bricks must be subjectedbefore they are charged into the kiln, and efforts are continually madeto simplify the manufacture by means of kilns in which the slurry may beburned directly as it comes from the mills. The so-called rotary kilnsrealize this. object to a certain degree in that they burn the slurrywithout a preliminary drying. Nevertheless the burned cement from thesekilns leaves much to be dethrough the kilndo not come in contact withevery particle. Thus ithappens that, besides a small proportion ofgoodcement clinker and a portion overburned, the bulk of the product fromthese kilns is underburned clinker-that is tosay,clinker not burnedthrough-because' owing to the continuous movement of the 7 mass only thesurface of the material is sintered, leaving an insuftlciently-sinteredcore. Such incompletely-burned cement is ill-fitted for use. In orderthat the mass may be systematically and uniformlysintered, a certainamount of rest and a constant even heating such as obtained in stage,shaft, or ringkilns are necessary.

By the present invention the processes of drying and burning areeffected separately, whereby a well-burned cement clinker is obtained.The slurry is dried and heated while it is in motion, whereas theburning and cooling are carried out while the material is at rest. Thefurnace is also devised so that the Serial No. 25,615. (No model.)

slurry may be charged into the kiln directly from the mills. p

In the accompanying drawings, Figure 1 is a longitudinal verticalsection of a kiln constructed in accordance with this invention, and Fig2 is a section on the line any of Fig. 1.

The kiln consists of a cooling-chamber c, a burning-chamber d, flues f,and a side or receiving chamber 1) over the burning-chamber, in whichthe dried slurry collects before it is burned, being fed thereto througha rotary cylindrical heating-chamber a t. Into the chamber 6 projectlaterallya number of fines f, that are arranged above and in alinementwith the bu rning-chamber d, with which they communicate by means of anintervening tapering neck 0. This neck merges at its wider upper-endinto the lower contracted.

end of a hopper formed at the lower end of chamber 5 by theinwardly-projecting slanting wall of fines f. Communication between thehopper and the neck a is controlled by a slide 8. The upper ends of theflues fex-tend into chamber b above the level of the ground materialwithin the same, so that the heatinggases are conveyed from theburning-chamber through the'fiues into the receiving-chamber and thencethrough the cylinder at to the' stack.

The kiln is worked as follows: .The ground material is mixed with waterin the conveyer g and charged in lumps through the pipe m into the farend of the drying-cylinder 25, where it is dried. It then passes to thepart a of the cylinder, which is lined with fire-brick, and where apreliminary heating and burning of the material occurs. The cylinder beinginclined downward toward the kiln and being in constant rotation, thematerial which it contains is kept moving toward the kiln. The cylinderis provided with rails Z, which enable it to revolve on the rollers 0when it is driven by the toothed gearing is p. This rotation may bealways in the same direction; but it is advantageous that it shouldalternate in direction, which. may be effected by any known form ofmangle motion. From the preheating-cylinder the mass falls into thechamber 19, where it remains until the material already in theburning-chamber dis completely burned and has sunk into the chamber e,owing to the withdrawal of clinker from the latter. The slide sis thenopened, and the contents of the chamber 1) are discharged into theburning-chamber d. The capacity of chamber 1) is such that it is filledduring the time occupied in the thorough burning of the clinker in theburning-chamber. The products of combustion and hot gases from theburning-chamber d pass up the fluesf, and with or without the aid of ablast, through the receiving-chamber b and the heating-cylinder a, tothe place where the slurry is charged, whence they escape through theflue 7b to the chimney. The hot gases thus come in contact with thematerial to be burned and dry and heat it before it arrives at thechamber 19, whence it is discharged, as already stated, into theburning-chamber (Z. The opening 6, through which the fuel is introduced,admits a rake for facilitating this discharge. The kiln may be providedwith an artificial draft. The slide 8 is not essential; but even when itis omitted the gases pass through the fines f.

It is specially to be noted that the slurry is charged into thedrying-cylinder without any binding material, thus making it up intobriquets, and previous drying is not necessary.

When the kiln is to be used for burning material already in the form ofdry lumps, such as limestone, these may be charged directly into thechamber 5.

VVhat I claim, and desire to secure by Letters Patent of the UnitedStates, is-

A kiln composed of a receiving-chamber, flues lying against the side ofsaid chamber, within the lower portion thereof, to form a hopper, aburning-chamber communicating with said hopper, a fuel-openingintermediate the burning-chamber and the flues, a coolingchamber belowthe burning-chamber, and a rotatable cylinder entering the upper portionof the receiving-chamber above the hopper, substantially as specified.

In witness whereof I- have hereunto signed my name in the presence oftwo subscribing witnesses.

IIERMANN SCHMIDT.

\Vitnesses:

L. BARNES, KARL SCHMITT.

